In situ Degradation Patterns of ‘Tifton 85’ Bermudagrass with Dried Distillers’ Grains Supplementation

Abstract

Season of forage growth and supplementation have the potential to affect digestion and animal performance. The objectives were to evaluate the ruminal digestion kinetics of 'Tifton 85' bermudagrass (T85) [Cynodon dactylon (L.) Pers. × C. nlemfuënsis Vanderyst] as affected by seasonality and rate of supplemental dried distillers' grains with solubles (DDGS). Samples were harvested in June, August, and October 2014. Six ruminally-fistulated steers were allocated to three pens. Pens (experimental unit) were randomly assigned one of three rates of DDGS: 0, 2.5, or 10 g kg -1 body weight (BW) as fed. Duplicate samples of each seasonality were inserted into the rumen of each animal en masse and removed sequentially after 2, 4, 8, 12, 24, 72, or 96 h. Degradation of dry matter (DM) decreased with increasing seasonality (P ≤ 0.01) and DDGS (P ≤ 0.04). The indigestible fraction (U) of DM from T85 was least (P < 0.05) for June (190 g kg -1 ), followed by August (337 g kg -1 ), and greatest for October (407 g kg -1 ). The U from T85 DM was not different (P = 0.47) based on rate of DDGS (312 g kg -1 ). There was an interaction of seasonality and DDGS for T85 NDF (P = 0.01) and ADF disappearance (P < 0.01). Increasing DDGS improved degradation of June but not October seasonality. Harvests from later in the season may have altered the cell wall structural profile, and increases in DDGS supplementation might have created an inhospitable rumen environment for fiberdegrading bacteria.

Ruminal degradation of Panicum grasses in three post-regrowth ages

“…The level of rumen degradability of CP can be variable between different forage species, which determines the availability of ammonia nitrogen in the rumen, and the proportion of amino acids from the diet and microbial protein, that reach the intestine, which are directed to tissue protein synthesis (25) . The concentration of crude protein is higher at the vegetative stages of forages and decline at the flowering stage, which may vary depending on differences between species, initial level of protein in the plant, stem and leaf proportions, content of fiber components in the cell wall and ambient temperature (15,21) .…”

“…The NDF colonization time (lag) (0.69 h) increased, leading to a decline in the rate of passage (1.14%/h) at the highest cutting ages. The colonization time of the fiber fraction represents the time between the start of incubation and ruminal degradation and is associated with the ability of rumen microorganisms to attach to the particles (21) , increasing when there is a greater proportion of lignified cell wall in the forage, makes it difficult for microorganisms to adhere. Associated with this effect, there is a reduction in ruminal degradation of the fiber fraction, as observed in this study, which can affect the ruminal passage rate and negatively imply the intake of DM.…”

“…In this sense, the assessment of the potentially degradable fractions in the rumen can determine the best time for harvesting the plant, associated with adequate nutritional value. The in-situ degradability technique is adequate to this end and allows quantifying the disappearance of nutrients over time, considering the real conditions of the rumen environment (19,21) . The objective of this study was to determine the chemical composition and in situ degradability of grasses of the genus Panicum at three post-regrowth ages.…”

Kudzu (Pueraria montana var. lobata) age variability effects on total and nutrient-specific in situ rumen degradation

“…Estimated parameter values of kudzu were similar to average values obtained from various forage species as reported by Mertens and Loften (1980), with a slightly lower rate of digestion on fibre content. Additionally, estimated D 0 and k d values for DM were greater than Tifton 85 bermudagrass as reported by Smith et al (2017). Meanwhile, both D 0 and U values of NDF or ADF were smaller than bermudagrass and lag time was also much shorter.…”

Forages and pastures symposium: an update on in vitro and in situ experimental techniques for approximation of ruminal fiber degradation

“…With modeling, IV and IS techniques can bring together measures of fiber, which are laboratory measures, to in vivo apparent digestibility and intake, which are animal-influenced measures, as a proxy to expensive and time- and labor-consuming feeding trials, which require much larger amounts of feedstuffs and more animal experimental units. Ranking of IV or IS results can help determine forages in breeding programs that are most suitable for advancement ( Foster et al, 2007 ), impact of genetic traits on potential animal performance ( McCuistion et al, 2017 ), the ideal maturity stage for harvest ( Foster et al, 2012 ), harvested forage preservation method ( Foster et al, 2011 , 2012 ), harvested forage preservation aids such as enzyme or microbial applications before ensiling ( Thomas et al, 2013 , 2014 ; McCuistion et al, 2017 ; Foster et al, 2019 ), alternative uses of row crop residues ( Foster et al, 2012 , 2019 ), supplementation regimes ( Smith et al, 2017 ), and among many other applications.…”